Multi-Hash Blockchain
(see also Encrypted Blockchain) A multi-hash Blockchain (mhBc) is a blockchain variant in which the chain is verified by more than just a single core hash-chain. By using multiple hash-chains, there is no benefit to the speed of consensus compared to simply using the 'least difficult' hashing algorithm. However, there can be benefits for the short-term memory of the chain with the other hash-chains forming a sort of RAM to complement the Hard Drive that is the core blockchain. Absolute Consensus Understandably, having different chains can imply that consensus is no longer guaranteed, since users obeying the rules of a different hash-puzzle will not see eachother's 'validated' blocks as being globally valid. However, a global consensus algorithm can be written in which blocks are considered validated only after multiple layers of hashing has occurred. As long as each layer of hashing is a true hash function, then it is impossible to pre-hash a block prior to the creation of the preceding block. This means that there are no 'head starts'. Decentralisation of mining power The core benefit of multi-hashed blockchains is that by forcing multiple layers of arbitrary hashing, the complexity of the solutions becomes guaranteed not by the limitations of modern computing power (which tend to scale to meet demand), but rather by the diversity of the encryption functions that compose the block solution. Selfish Mining There is always potential for selfish mining, whereby mining syndicates (or 'pools') choose to attempt to complete solutions prior to announcing them publically. However, this can very elegantly be limited by applying a final hash function to the block that is dependent on the moment of submission. In this sense, once the block has been publically submitted, there is still the opportunity for any other miner (from outside of the pool) to solve that final hash and claim the majority of the reward. Global Validity The only way to achieve global consensus is to have a global contract that specifies the minimum criteria for block validity. Sub-chains can apply their own meta-criteria to filter out transactions that relate to their subchain, but if they accept the core contracts of the network then they accept a global consensus on which blocks are valid. Subcontracts can merely assign subjective value to transactions within those globally valid blocks: * A 'locally valid' transaction is any transaction within the core chain that is also deemed valid to a specific node or pool of nodes on that network * A 'locally invalid' transaction would be a transaction that is accepted by the core chain, but is disputed by a specific node or pool of nodes as being unacceptable under their own subcontracts Subcontracting When nodes are allowed to invalidate 'globally valid' transactions according to their own 'subjective chains' this can cause failures in consensus. Instead of being able to dispute and remove 'locally invalid' transactions, multi-hash blockchains tend to allow subcontractors to devalue the assets of untrusted nodes. Hence, if Alice sends Bob 100 Red tokens and Bob sends her back 20 Blue tokens, the natural assumption is that the local value of a Blue token is 5 Red tokens (at that moment in the chain's imaginary spacetime) However, subcontractors for the Blue chain might argue that trades like these actually occur as part of an off-chain contract whereby Alice also provides Bob with some real-world asset, hence the true local value of Bob's 20 Blue tokens is actually greater than 100 Red tokens. Subcontractors might design prediction and assumption matrices that help them to categorise transactions and develop sophisticated measures of local and global values for the sub-tokens of each sub-chain.Category:Blockchain Category:Quantum Cryptography